As discussed in U.S. Pat. No. 6,950,033 to Guyre, entitled “Door Bolt Alarm,” which is incorporated by reference herein, it is desirable for purposes of home security and homeowner reassurance for a user to be able to know for certain whether a door to their home, such as a front door, is properly closed and that the deadbolt is properly engaged. Security systems, building automation systems, and HVAC systems all benefit from knowing the state of doors, such as whether they are open or closed, locked or unlocked, and the like. Several known deadbolt systems are able to verify that a bolt of the deadbolt system is either extended or retracted and are able to communicate this status in various ways to a user. However, the status of the bolt as being extended or retracted is not necessarily indicative of the true security state of the door. For example, it may be the case that the bolt is extended, but that the door is still partially open. Moreover, many existing systems require wiring to be installed in door frames and/or door jambs, which can be expensive and complicated to install and maintain.
Thus, existing systems cannot reliably verify that a door has indeed been shut and that the deadbolt has indeed been properly engaged. Moreover, existing systems are complex and often include a multitude of sensors and require significant wiring.